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Methylene Chloride Safety Hazards

Methylene chloride or dichloromethane is a molecular compound with the formula CH2Cl2. It is a colorless liquid that evaporates readily and exudes a pleasant sweetish odor. While methylene chloride is primarily used in industry, it's also found in some household products like spray paints and paint removers as well. It's important to be aware of the possible health hazards posed by methylene chloride when you work with products containing this chemical.

  1. Inhalation

    • Since it is highly volatile and evaporates easily, the primary route of exposure to methylene chloride is through inhalation. The scent can be detected at concentrations of 200 parts per million (ppm) or above. According to the Agency for Toxic Substances and Disease Registry (ATSDR), high concentrations of 8,000 to 20,000 ppm or above can cause unconsciousness and death. Exposure to concentrations of 800 parts per million or above may cause symptoms similar to drunkenness or intoxication, together with dizziness, nausea and tingling in the extremities. The ATSDR notes that while at least one study found that levels of 490 ppm or above caused eye irritation, the symptoms were temporary.

    Skin Contact and Ingestion

    • According to the JT Baker Material Safety Data Sheet, prolonged direct skin contact may cause skin redness or burns. Ingestion can cause vomiting, irritation of the gastrointestinal tract and other symptoms similar to those of inhalation.

    Carcinogenicity

    • According to the California Environmental Protection Agency, the evidence suggests prolonged inhalation or ingestion of methylene chloride may cause cancer. The EPA classifies methylene chloride as a probable human carcinogen and the Occupational Health and Safety Administration has set the maximum occupational exposure limit at 25 ppm.

    Flammability

    • Dichloromethane is not especially flammable, but given the right conditions it can will burn, so appropriate safety measures should always be observed. Dichloromethane can autoignite at temperatures of 1033 Fahrenheit or above, and the vapor can form a flammable mixture with air at temperatures of 212 Fahrenheit or above. It's recommended that dichloromethane be stored and used separate from any source of heat, open flame or electrical arcs.

    Chemical Hazards

    • Dichloromethane should never be stored together with strong oxidizing agents, strong bases, nitric acid or reactive metals. It may degrade rubber and certain plastics and should be stored accordingly.

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